Ignore logging configuration parameters if they are actually global.
Ignore logging configuration parameters if they are actually global.

Every config section automatically has the global defaults, but those
are not relevant for the logging section.  Added logic to ignore the
default entries if they are not valid for log level configuration.

stdweird/aquilon,guillaume-philippon/aquilon,guillaume-philippon/aquilon,quattor/aquilon,guillaume-philippon/aquilon,quattor/aquilon,quattor/aquilon,stdweird/aquilon,stdweird/aquilon